Senescent Ventricular Dysfunction: Issues Related to Cardiopulmonary Bypass

Abstract

The mean age of the open-heart surgical patient is increasing every year. Therefore, it is logical to define the aging-related changes in cardiovascular function. This study set forth to define the major molecular and performance alterations that occur in the left ventricle related to advanced aging or senescence. In the human, vascular pathologies usually accompany left ventricular dysfunction. The aim of this study was to associate the altered left ventricular mechanics with molecular pathways in mice who lacked these associated vascular pathologies. This study compared the left ventricular function of two groups of mice (N = 20 each), 6 months old and 16 months old (senescent). The mice were anesthetized with urethane and α-chloralose, and a Millar 1.4 Fr. conductance micromanometer catheter was placed into the left ventricle for acquisition of pressure-volume loops. Heart tissues were collected immediately for analysis of cGMP concentrations. The cardiac index, preload recruitable stroke work, and the slope (Ees) of the end-systolic pressure volume relationship were significantly less in the senescent group compared to the young mice. It was concluded that the aged heart has significantly reduced systolic and diastolic dysfunction compared to the young heart function and that this dysfunction may be related to pathways leading to increased myocardial cGMP concentrations.